In the days when he could walk and talk properly, Craig Kellenberg was a busy drug dealer who loved to stay awake for days at a time on a methamphetamine binge with his mates.

Now, after having four strokes by the age of 30, he struggles to sign his name and find the right words to say how he feels.

Mr Kellenberg has an acquired brain injury as a result of his strokes, which were caused by drug use.

He is one of many thousands of young Australians living with a stroke-related disability.

But it is hard to know just how many drug-related stroke victims like Mr Kellenberg are in the community because, as stroke specialists will tell you, the link between the two has not been adequately researched.

Neurologist James Leyden said he had seen many case studies where meth had caused strokes but there was a lack of population-based evidence.

"Meth has been associated with strokes but it's a huge area in need of more research," he said.

"It's absolutely frightening, some of the brain scans of amphetamine users are awful."

Dr Leyden said it was not widely understood that drugs of all varieties, from marijuana to ice, could cause strokes of all kinds.

Some people could have a stroke the first time they used a drug because their brain could be particularly sensitive to it.

"In my opinion, we have no proven link but marijuana is still probably the biggest of our problems," he said.

As Dr Leyden explained, drug use can lead to strokes in different ways, from making blood pressure soar and blood vessels "explode" to causing irregular heartbeats which could lead to clots.

Not expected to survive the night

For Mr Kellenberg, his last and most devastating stroke came after he had just smoked methamphetamine and was driving around Bunbury to seal a drug deal.

"I could feel it coming," he recalled.

After taking the money from his drug mate, he could not talk but still got behind the wheel of his car, only stopping when the car landed in a ditch.

Physically I am improving immensely ... it used to take me 10 minutes to write a whole [text] message, now it takes 20 seconds.

Craig Kellenberg, former drug user

He said eight police officers had to prise him out of the car, his affected right arm locked tightly around the steering wheel while his left hand refused to let go of his clutch of drug money.

Hospital doctors told his sister that there was no way he would survive the night.

He has lived to tell the tale in his slow, laboured and often faltering speech, an obvious marker of his brain injury.

Two years on from his biggest stroke, Mr Kellenberg is still trying to rebuild his life.

Once a right-hander, he has struggled to learn to write again with his left hand.

His main problem is aphasia, or difficulty in speaking and finding the right words, as well as weakness down the right side of his body.

"The wobble in my walk shits me because I have got to live with this for my whole life," he said.

"Physically, I am improving immensely. I notice I am getting a hell of a lot better at using my iPad and iPhone now.

"It used to take me 10 minutes to write a whole message, now it takes 20 seconds."

Unexpected life leads to role as educator

While he is also frustrated by his unsuccessful attempts to find a regular job, he is doing valuable work educating school children about the perils of drug use through his work as an ambassador for Headwest, a support and advocacy service for people with acquired brain injuries.

He talks to high school students as part of the PARTY (Prevent Alcohol and Risk-related Trauma in Youth) program at Royal Perth Hospital which exposes teenagers to real-life examples of trauma caused by risky behaviours.

Mr Kellenberg tells the students how he first started using crystal meth at 21 when he was working in security in Bunbury bars.

He had his first stroke at 22 in a bar, during which his vision became blurred and he lost the ability to speak.

That did not stop him from continuing to deal and use crystal meth, and he would often not sleep and eat for days at a time.

He weighed 79kg, at least 20kg underweight for his height.

He later spent more than four years in prison for dealing drugs and after his release jumped straight back into the Bunbury bar scene, taking and dealing drugs, until his fourth and biggest stroke in November 2013 felled him.

As a result, he lives at Brightwater Oats Street rehabilitation facility in Victoria Park which looks after young people with acquired brain injuries, with the aim of keeping them out of nursing homes and teaching them to live independently in the community.

It is not the life he expected, but as research for the Australian Stroke Foundation shows, he is one of many thousands of young Australians whose lives have been dramatically changed by strokes.

The Deloitte Access Economics study found that almost 14,000 Australians up to the age of 40 were living with a stroke-related disability in 2012.